Cannot send email due to wrong required form of email

I have workflow that sends generated email, but it fails with error message:

2015-12-10 10:10:48,258 [416] ERROR CZ.Advantages.Asap.Workflow.WorkflowEngine [(null)] <martin.smid> - The specified string is not in the form required for an e-mail address.

I am pretty sure I have right context mapping and selected email is in standard format. Workflow Trace shows correct values.

Hi, have you tried to turn on trace on your workflow? (try to set trace Architect and Client as well) You can then examine your workflow in architect (Ctrl+t). There you can find out what really is sent to the service sending mail.

The problem is that the default e-mail is not set correctly in web.config even though the sender e-mail si set in the mail message.